The formulation of ultra-mild personal cleansing preparations has become a focus of great interest. When people wash and scrub their skin with various surface-active preparations frequently, mildness is very important. Ideal cleansers should be cost effective, cleanse gently and rinse well. Most toilet bars fall short in this respect.
Synthetic detergents are relatively expensive. None of the synthetic products as yet matches the low cost of soap when compared on a 100% active ingredient basis.
The use of synthetic detergent surfactants in soap bars is well known, being documented in U.S. Pat. Nos.: 2,988,511, Mills et al., issued Jun. 13, 1961; 3,043,778, Kelly, issued Jul. 10, 1962; and 3,598,746, Kaniecki et al., issued Aug. 10, 1971, said patents being incorporated herein by reference.
U.S. Pat. No. 4,180,470, Tokosh et al., issued Dec. 25, 1979, incorporated herein by reference, discloses a method for making improved acyl isethionate detergent bars with from 2-6% of sodium alkoxy hydroxy propane sulfonate (a synonym for alkyl glyceryl ether sulfonate) with alkyl chains of from 8 to 22 carbon atoms in conjunction with a small amount of sodium chloride.
Commonly assigned U.S. Pat. No. 4,820,447, Medcalf et al., issued April, 1989, incorporated herein by reference, discloses a mild soap bar comprising a polymeric skin mildness aid. Commonly assigned U.S. Pat. No. 4,985,170, Dawson et al., entitled "In Beta-Phase Bar Form Containing Soap, High HLB Nonionic Surfactant, and Water-Soluble Polymer," issued Jan. 15, 1991, and U.S. Pat. Nos.: 2,988,511, supra; 2,989,547, Whyte, issued Jun. 20, 1961; 2,999,068, Pilcher et al., issued Sep. 5, 1961; and 3,024,273, Whyte et al., issued Mar. 6, 1962, are all incorporated herein by reference.